The aim of the former editions remains unchanged in the present updated version, namely to put forward a general and comprehensive review on complement. It is intended not only for individual investigators working in this specific field, but also for those who are less familiar with it. Students or younger scientists will hopefully be stimulated and attracted by the fascination of complement biology. Again, it was clear from the beginning that the field has experienced an explosive expansion in various directions and continues to accumulate data too large to be dealt with by a single author in a critical and coherent manner. The editors are grateful that the invited authors, all of them leading scientists in their field, helped again to make The Complement System a true mirror of the state of the art. Some parallels in the various chapters were accepted, as was a particular emphasis on newer developments in some chapters.

1 Components and Reactivity

1.1 Components
1.1.1 Factors of the Classical Pathway
1.1.2 Components of the Alternative Pathway
1.1.3 Late Components
1.2 Reactivity
1.2.1 Classical Pathway of Activation
1.2.2 Lectin Pathway of Non-self Recognition
1.2.3 Alternative Pathway: Activation and Regulation
1.2.4 Complement Attack Phase
1.2.5 Control Mechanisms
1.2.5.1 Membrane Cofactor Protein (CD46) and Decay-Accelerating Factor (CD55)
1.2.5.2.1 Control of C5b-9 by Fluid Phase Factors
1.2.5.2.2 Membrane-Bound Inhibitors of C5b-9
1.2.5.3 Interspecies Incompatibilities of Complement Factors and of Regulators
1.3 Surface Receptors and Signaling Pathways
1.3.1 Receptor for C1q
1.3.2 Receptors for Human C3 Fragments
1.3.3 Receptors for C5a, C3a, and Factor H
2 Biologic Functions
2.1 Complement in the Induction of Antibody Response
2.2 Maintenance of Immune Complex Solubility and Immune Adherence
2.3 Interaction with Effector Cells
2.3.1 Leukocyte Mobilisation/Recruitment
2.3.2 Chemotactic Peptides
2.3.3 Cellular Responses to Activation Products
2.4 Host Defense Against Infection
2.4.1 Defense Against Bacteria
2.4.2 Complement-Dependent Virus Neutralization
2.4.3 Evasion of Complement-Mediated Damage by Microorganisms
2.5 Possible Role of Complement Regulators in Reproduction
2.6 Network Interactions of the Complement System with Other Serum Mediator Systems
3 Pathology
3.1 Complement Deficiencies in Animals: Impact on Biological Functions
3.2 Complement Deficiencies in Humans
3.2.1 Inherited and Acquired Deficiencies of C1 Esterase Inhibitor in Humans
3.2.2 Deficiencies in the Classiral Pathway
3.2.3 Deficiencies in the Alternative Pathway: Factors I and H
3.2.4 Deficiency in Terminal Reactivity
3.2.5 Deficiency in Lysis Control Proteins
3.2.6 C3 Receptor Deficiencies
3.3 C3 Nephritic Factor
3.4 Complement in Inflammation
3.5 Role of Complement in Graft Rejection
3.6 Complement Activation on Artificial Surfaces in Biomedical Therapies
3.7 Adverse Reactions to Drugs
4 Complement Manipulation In Vivo
5 The Clinical Laboratory: Testing the Complement System.